


Once a Day

by followthattardis



Category: Supernatural
Genre: Angst, Canon-Typical Violence, Castiel Bears the Mark of Cain (Supernatural), Episode: s15e09 The Trap, M/M, Ma'lak Box (Supernatural)
Language: English
Status: Completed
Published: 2020-01-23
Updated: 2020-01-23
Packaged: 2021-02-27 08:00:41
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,407
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22373761
Author URL: https://archiveofourown.org/users/followthattardis/pseuds/followthattardis
Summary: Castiel has just enough control left over his body and mind that he steps into the Ma’lak Box on his own.
Relationships: Background Eileen Leahy/Sam Winchester, Castiel/Dean Winchester
Comments: 49
Kudos: 190





	Once a Day

**Author's Note:**

> Oh boy. I have no idea how this happened.
> 
> I was supposed to be working on the sequel to A Crash Course in Computer Safety (still am though, not to worry), but as soon as the episode aired, I knew I had to write something. Of course, I chose angst. I read some lovely codas where Dean has to force or trick Cas into the Ma'lak Box; this is my take on what would happen if Cas went willingly.

Castiel has just enough control left over his body and mind that he steps into the Ma’lak Box on his own.

It’s a small victory none of them thought would be needed. The Mark wasn’t supposed to affect Castiel as much as it used to affect Dean – his grace, while wonky and unreliable these days, should still provide a sufficient buffer against the magnetic pull of the fresh brand on his forearm. And it did, for months after Chuck had been safely locked away. The Mark would flare up occasionally, itching and throbbing like a restless beast trapped under his skin, but Castiel’s grace soothed it, lessening the ache to a manageable level. It wasn’t ideal, but he could learn to live with it. Besides, it was more than worth it to finally take Chuck off the board. Without him there to meddle, they were free and it seemed like maybe, maybe the eternal storm that always brewed over their heads had cleared for good.

They went back to hunting, all four of them: Castiel, Dean, Sam, and Eileen, who moved back to the bunker as soon as she was certain nobody was pulling her strings anymore. For a while, life was good – in fact, it was better than Castiel ever remembered it being. There were movie nights and game nights; there were easy, run-of-the-mill ghost hunts and days off; there was laughter echoing throughout the bunker; there were Sam’s eyes lighting up whenever Eileen walked into the room, there was Dean teasing him for being whipped, and Castiel watching them all fondly, his palm resting over the raised skin on his right forearm, hidden safely under his coat sleeve. It prickled, but it didn’t matter. He would adapt.

After a few months, Sam found them a case in Leadville, Colorado. Two bodies had showed up with their hearts missing, a fact the local authorities attributed to wild animals but Sam and Dean immediately deemed to be the work of werewolves. A simple, straightforward affair; nothing three skilled hunters and an angel couldn’t handle. Armed with silver knives and guns loaded with silver bullets, they went in expecting a lone werewolf or two, probably freshly turned judging by how carelessly the bodies had been disposed of.

The pack they stumbled upon was _huge_. Castiel has no memory of the fight, though it must have been chaos if the end result was anything to go by. He only remembers the split second of shock and panic as he realized they were surrounded and outnumbered, and then it was over. He was kneeling on the ground, angel blade clutched in his hand, chest heaving, blood splattered all over his face, his clothes, Dean—

Dean, who was gripping him by the shoulder and saying his name over and over again, pleading with him to stop. Grounded by the sound of Dean’s voice and the weight of his touch, Castiel managed to blink back the haze, and saw that the werewolf he had been carving into was long dead.

He let the blade clatter to the ground. He let Dean pull him upright, away from the carnage. He let Dean haul him back to the Impala while Sam and Eileen stayed behind to torch the whole place, sending the evidence of his transgression up in flames. He let Dean wipe the blood from his face and divest him of his stained coat. He let the silence sit and fester between them, unwilling to articulate what they both already knew. It was only once they were back home, seated opposite each other at the war room table, that Castiel found the strength to say: “Dean, I need you to rebuild the Ma’lak Box.”

He’d anticipated the vehement “No” before it left Dean’s mouth, but it didn’t make anything easier.

Leaning across the table, he reached out to cover the back of Dean’s hand with his palm. “It’s just a precaution. In case I lose control like that again.”

“No,” Dean repeated, clipped and angry. “You haven’t hurt anyone who didn’t deserve it. Those were monsters, Cas.”

Castiel sighed, glancing down at his own fingers resting ever-so-gently over Dean’s knuckles. A part of him clung to the knowledge that he was still capable of such delicate touch. “Had they been human and attacked us, I might have done the same thing. Would it be okay then?”

Dean’s throat clicked loudly, bobbing with an audible swallow. For a long moment, he didn’t say anything. Then: “How long has this been going on?”

Castiel closed his eyes.

“Since the beginning, hasn’t it? Since the moment you took on the damn thing. Fuck, Cas, why didn’t you say something? We coulda been searching for a solution this entire time—”

“There is no solution,” Castiel cut in. “We’ve been through this before, Dean. And I thought my grace would be enough to keep that darkness at bay, I truly did. But today, I— Dean, I don’t remember anything. I blacked out and the Mark took over. I could’ve hurt you by accident without even noticing. This cannot happen again. Promise me you’ll rebuild the box.”

“Cas—”

“Promise me.”

It was with sorrow etched deep into the lines of his face, but Dean promised.

Once repaired from the damage it had sustained after Jack had blasted it open, the Ma’lak Box sat in the bunker’s dungeon, a grim reminder of the road down which Castiel was headed, while their lives started slowly falling apart around them.

Dean wouldn’t let him tag along on hunts anymore, convinced that being around that kind of violence would send Castiel spiraling. But the monsters continued to prowl, more and more gruesome headlines popping up all over the country and not enough hunters to deal with them. Benched against his will and at the most inopportune time, Castiel grew frustrated and agitated. As his grace flickered in and out, exhausted and depowered, the Mark took a stronger hold. The bloodlust coursed through his veins like hot lava, yearning for a release he kept denying it. He was a powder keg, and it was only a matter of time before a stray spark came along.

Then, Claire died.

It was the sort of rage Castiel had never experienced before. It pierced through him like a white-hot skewer, turning him deaf and blind against everything that wasn’t a thumping pulse repeating _Punish them, punish them, punish whoever did this._ Had his mind been clearer, he would have recognized it as the same grief-fueled wrath that made Dean go on a rampage after Charlie’s death, that made him kill an innocent boy and beat Castiel bloody.

But he didn’t pause long enough to make that connection. Wrenching himself free from Dean’s preemptive grip, the rush of blood in his ears drowning out Dean calling out for him, he stormed into the bunker’s garage, took the first car his eyes fell on, and drove to Sioux Falls in one go without stopping at a single traffic light. He hit a police officer who tried to pull him over for speeding, and left him crumpled on the side of the road. He found Jody and slammed her against the wall, lifting her off her feet until she told him where to go next. He wiped the whole vampire nest her and Claire had gone up against, slashing and carving his way through them without a single thought until he was the only one standing, drenched in gore and viscera from head to toe.

When Sam and Dean caught up to him a few hours later, they found him curled up against an old industrial freezer the vampires used to store blood drained from their victims. He must have made a grisly sight – he could feel the hair matted against his forehead, the flakes of skin underneath his fingernails – but it didn’t stop Dean from dropping to his knees and cupping his filthy face in his hands. The desperation with which he choked out Castiel’s name lifted any residual bloodlust, and their eyes met; Castiel’s wide, Dean’s wet.

What Castiel meant to say was, “I’m sorry.” What came out was, “We have to do it now.”

From six inches away, Dean stared at him, the words he was turning over in his mind written plainly on his face. All those Winchester mantras like _There must be another way_ , and _We’ll think of something_ , and _You can fight it_ ; familiar and hopeful and useless.

There was no resisting this. Dean understood it better than anyone.

With Sam’s help, they hauled Castiel to his feet and took him home, one last time.

Even now, glancing down at the metal bottom of his coffin, Castiel wonders if there was something they might have done differently. The Mark rages against him, angry and scared as if it can feel the warding carved meticulously into the sides of the Ma’lak Box, but the bloodbath Castiel has left behind in Sioux Falls sated it enough that even the measly dregs of his grace can reign it in. Not for long; just long enough for Dean to slam the lid closed.

“We could try the angel cuffs,” Dean says.

When Castiel turns around to face him, Dean is standing by the side of the box, hands clamped over its edge in a white-knuckled grip. His jaw is clenched, bottom lip caught between his teeth. He looks like he’s in pain.

“They would stop working as soon as I became more monster than angel,” Castiel explains patiently. The Mark throbs, and he grunts, steadying himself with a hand against the open lid.

“Cas?”

Through gritted teeth, Castiel manages, “I’m fine,” then sucks in a sharp breath when the pulsing continues, red, violent, irresistible. The Mark has cottoned on to what’s happening, and it won’t go down without a fight. “We should hurry.”

Without waiting for Dean’s response, he lies down inside the box, flat on his back with his hands folded over his chest. His entire right arm hurts like somebody has jammed a needle into the dip of his elbow and started twisting, the ache radiating up towards his shoulder and spreading to every corner of his body. Caught up in his pain, shuddering as if from a fever, Castiel startles when Dean’s palm comes to rest on his cheek. It’s warm, but still pleasantly cool compared to the fire raging under Castiel’s skin.

Dean bends over the side of the Ma’lak Box, his thumb rubbing over Castiel’s jaw. His eyes are red-rimmed, and even through the roar of the Mark’s mindless rage, Castiel can still feel his longing.

With a mixture of horror and gratitude, he realizes he will be able to feel it even once the Ma’lak Box closes forever, sealing him in a living death. He’ll be able to feel it until the day Dean dies or forgets, and at this point, Castiel can’t decide which is worse.

“Dean,” he says, wrapping his fingers around Dean’s wrist. His veins are aflame, vision blurring, but if he can just have this one thing— “Will you do something for me?”

Balancing himself with a hand against the lid, Dean leans closer, his upper body almost entirely inside the box now. “Anything you want.”

“You don’t have to, if it’s too much, but would you— would you pray to me?”

Dean blinks at him. His hand stills against Castiel’s cheek.

“It doesn’t have to be often,” Castiel rushes to add. He shouldn’t be dragging this out, not when the Mark can take over at any second, but he thinks the prospect of being allowed to hear Dean’s voice again might be the only thing still keeping him lying here instead of struggling for freedom. “It could be once a week, or a month. It can be short. Tell me what book you’re reading, what you’ve eaten for breakfast. Anything. Just talk to me.”

A tear slides down the side of Dean’s face. “Fuck.”

Castiel knows that this is a lot to ask, maybe too much. He’s probably being selfish, forcing that kind of one-way communication on Dean. It’s a good thing Dean is refusing him. It’s for the best. Without that constant reminder, he will be able to move on.

But once that last hope is snuffed out, the Mark burns ever hotter, and Castiel feels himself slipping into a frenzy. He can’t do this. He has to get up, shove Dean aside and make a run for it, has to kill something just to make all this pain go away, it’s too hot, too much, what was he _thinking_ , he needs, he needs—

Dean presses their lips together. He cradles Castiel’s jaw with gentle, shaky hands, like Castiel isn’t a ticking timebomb – like he’s the most precious thing Dean’s ever held. He kisses him for the first and last time, chaste and soft.

“Of course I will,” he whispers. His mouth is wet, whether from saliva or tears or the blood seeping from Castiel’s bitten-through cheek, it’s hard to tell. “Every day. Every fucking day, Cas.”

Castiel exhales shakily against Dean’s mouth, flooded by bittersweet relief.

The promise strengthens his resolve, and the Mark _screams_ , writhes like something alien trying to burst through the surface of his skin. Castiel’s palms slap against the sides of the Ma’lak Box.

“Close the lid, Dean.”

Dean clutches Castiel’s face and doesn’t move.

“Please,” Castiel begs. “It’s only going to get worse.”

Slowly, Dean’s hands withdraw. His palm comes to rest over Castiel’s chest, a pointless reassurance of the heart thumping wildly inside, then it’s gone.

They look at each other. Dean’s eyes are red and puffy, fresh tears clumping his eyelashes and running down the bridge of his nose, making the freckles there stand out all the more prominently. He’s so beautiful, and Castiel loves him with every wretched atom of his being.

It would be too cruel to say it aloud now, so his final words to Dean are, “It’s okay.”

They part the way they met, all those years ago in the pit: with a glance at someone consumed by an evil that wasn’t his to carry.

The lid snaps shut.

The locks click.

Through the thick sheet of metal, the last thing Castiel hears of the outside world is a muffled sound of a body slumping over his coffin.

*

It takes four hours, twenty-nine minutes and seven seconds.

_Cas? You there?_

_This is day one._


End file.
